Adjustment needed for Shaft Hole Diameter Tolerance

[willbearfruits]

Issue Description

Users may experience the shaft hole being too tight or too loose depending on their 3D printer's calibration.

Current Behavior

The shaft diameter in the generated STL matches the exact value provided in the parameters (or the default). 3D printing slicing usually shrinks holes slightly.

Proposed Solution

• Add a user-configurable 'Tolerance' or 'Horizontal Expansion' parameter in the settings.
• Or, default to a slightly larger internal diameter (e.g. +0.2mm) for common fits.
• Investigate best practices for D-shaft and Knurled shaft tolerances.

Workaround

Currently, users are advised to manually increase the 'Shaft Diameter' parameter by 0.2mm - 0.4mm.